This invention relates generally to clamp binders for holding sheet material such as maps, blueprints and plans. More particularly the invention relates to new configurations for such clamp binders as well as to a new support structure for horizontally suspending new and known clamp binders.
In vertical filing systems, clamp binders are used to bind large sheets of material including engineering and architectual plans and drawings, maps, specifications, and blueprints. The clamp binder grasps the sheet-like material along an edge thereof to frictionally hold the material in the binder. The binder may then be suspended in a substantially horizontal position from a support structure whereby the sheet material hangs vertically from the clamp binder. Such vertical filing systems preferably provide for ease of examination, handling and storage of sheet material.
Known binders include "three piece binders" such as characterized in Canadian Pat. No. 604,233 to Schneider and U.S. Pat. Nos. 3,891,093 and 3,308,831 to Petrie and Kritske, respectively. These three piece binders include an inverted channel member carrying therein a pair of clamping members.
The upper edges of the clamping members are hinged inside the channel and coupled to a threaded bolt extending upwardly through the channel to a wing nut on the exterior top surface of the channel. Turning the wing nut draws the bolt upward, rotating the upper edges of the clamping members about their hinges, and causing the lower edges of the clamping members, which protrude from the channel, to clamp about sheet material to be held.
Some "two piece binders" have also been proposed as in U.S. Pat. No. 3,069,737 to Schneider. These two piece binders are characterized by two clamping members hinged together with threaded bolts and wing nuts co-operating to draw complementary edges of the clamping members together to grasp sheet material therebetween. Two piece binders proposed to date have not proved satisfactory and suffer from a number of disadvantages. One disadvantage is that they do not provide a satisfactory hinge between the clamping members. Another disadvantage is that the configurations of the clamping members do not permit efficient transfer of tensioning forces created by the bolt and wing nut into clamping forces acting on the sheet material to be held.
A disadvantage common to most two and three piece binders is that the conventional wing nuts used to create the clamping forces are located on the exterior top surface of the binder. Known binders may most conveniently be laid on their side, as on a desk top, to insert sheet material between open clamping members. With binders having wing nuts mounted on the top surface of the binder, the desk top typically interferes with the wing nuts and, in any event, the proximity of the wing nut to the desk top prevents easy and satisfactory manual turning of the wing nuts to tightly clamp the binder onto the sheet material being inserted.
Most three piece binders are arranged so that the sheet material will hang straight down from the channel member between symmetrical clamping members. Known two piece binders fail to satisfactorily achieve such a symmetrical arrangement. Those two piece clamps which have attempted to approximate a symmetrical arrangement have found it necessary to locate the adjusting wing nuts on the top surface of a channel like member forming one of the clamping members. Known two piece clamp binders have failed to provide symmetrical grasping members in combination with side mounted wing nuts.
Known systems for hanging binders include a simple system comprising two parallel, spaced, horizontal bars across which a binder may be suspended with one end of the binder supported on one bar and another end of the binder supported by the other bar. Such a system is for example referred to in U.S. Pat. No. 3,308,831 to Kritske. Parallel bar systems have the disadvantage that when a number of binders are stored adjacent each other, great difficulty is to be experienced in lifting out any intermediately located binder, particularly having regard to the substantial weight of a loaded binder.
To overcome this problem, hinged bracket support systems have been proposed such as in Canadian Pat. No. 671,574 to Schneider and U.S. Pat. No. 3,211,892 to Morcheles. In these systems, a number of adjacent brackets are placed at spaced intervals along a wall with each bracket hinged to rotate about a vertical axis. Each bracket independently receives and supports a binder such that the bracket and binder will rotate as a unit. With binders suspended side-by-side on separate brackets, access to any binder is facilitated by rotating adjacent binders away therefrom. In such systems, coupling means are provided to couple the binder to the bracket, typically coupling the binder to the bracket at two separate points of support. Known hinged bracket support systems have the major disadvantage that, in order to couple the binder to the bracket or disengage the binder from the bracket, substantially the entire weight of the binder must not only be lifted but must also be carefully manipulated. Prior art vertical filing systems thus fail to provide a system in which access to and removal or replacement of the binder can be carried out quickly and with a minimum of effort.
Another disadvantage of hinged bracket support systems is that after adjacent binders have been pushed aside to rotate away from the desired binder, no means is provided to automatically swing the binders back to a normal storage position, in which position typically a minimum of space is occupied by the suspended binders.
With an understanding of hinged bracket support systems, a mutual disadvantage of hinged bracket support systems and known two and three piece binders may be pointed out. In many cases where a binder is coupled to a hinged bracket support system, the disadvantage arises that the effective location of the coupling means coupling the binder to the bracket will be such that the center of gravity of the binder and grasped sheet material is not effectively centered about the coupling means. The off-centered weight of the binder and sheet material disadvantageously produces a force moment attempting to rotate the suspended binder about its longitudinal axis. This rotational moment makes coupling and disengagement of the binder more difficult in that in manually manipulating the binder, not only must the weight of the binder be supported but the rotational force must be overcome to achieve a proper orientation of the binder for coupling or disengagement.